Taylor dispersion analysis is an absolute andstraightforward characterization method that allows determiningthe diffusion coefficient, or equivalently the hydrodynamicradius, from angstroms to submicron size range. In this work,we investigated the use of the Constrained Regularized LinearInversion approach as a new data processing method to extractthe probability density functions of the diffusion coefficient (orhydrodynamic radius) from experimental taylorgrams. Thisnew approach can be applied to arbitrary polydisperse samplesand gives access to the whole diffusion coefficient distributions,thereby significantly enhancing the potentiality of Taylordispersion analysis. The method was successfully applied toboth simulated and real experimental data for solutions ofmoderately polydisperse polymers and their binary and ternary mixtures. Distributions of diffusion coefficients obtained by thismethod were favorably compared with those derived from size exclusion chromatography. The influence of the noise of thesimulated taylorgrams on the data processing is discussed. Finally, we discuss the ability of the method to correctly resolvebimodal distributions as a function of the relative separation between the two constituent species

We use dynamic light scattering to investigate the effects of charge polydispersity and chargeresidence time on the dynamics of a micellar system. While in the corresponding uncharged system onlyone exponential relaxation is observed, two relaxation modes are seen when charging the micelles byadding charged co-surfactant molecules with a long residence time. We attribute the existence of thesetwo relaxation modes to the combined effect of size polydispersity and charge polydispersity, i.e. frozenfluctuations of the number of charges per micelle. Further support to this scenario is provided by controlexperiments on a similar charged system, but where the charge residence time is short compared to thetime scales probed by dynamic light scattering. Here, charge polydispersity is effectively suppressed dueto the rapid exchange of charged molecules between micelles and only one single relaxation mode is seen,thereby demonstrating the key role of frozen charge fluctuations in the complex dynamics of our micellarsystem.

We present magnetotransport measurements performed on Cd3As2 samples. Our results confirm the existence of 3D Dirac fermions in this material with a π Berry phase. A metal-insulator transition driven by the magnetic field is also observed for B < 1 T. Finally the in situ rotation of the sample reveals that the Fermi surface is a weakly anisotropic ellipsoid.

Genome processing relies on the intracellular localization and dynamic assembly of higher-order nucleoprotein complexes. In bacteria, the mechanism of assembly for the most widespread partition systems, ParABS, responsible for active DNA segregation remains elusive. We have combined super-resolution, genome-wide, biochemical and modeling approaches to investigate quantitatively the formation of the nucleoprotein complex organized around the centromere-like sequences, parS. We found that the active confinement of nearly all ParB proteins around parS, observed at the single molecule resolution, relies on a network of synergistic interactions involving protein-protein and protein-DNA interactions. Our physico-mathematical modeling of ParB binding pattern revealed that ParB binds stochastically in the vicinity of parS over long distances. Based on our findings, and consistent with previous data, we propose a new model that relies on a nucleation and looping mechanism leading to the formation of a dynamic lattice for the partition complex assembly. We thus provide new bases to model the DNA segregation process. Our original assembly model may also apply to many unrelated proteins that self-assemble in superstructures through nucleation centers.